[llvm] [GlobalISel] Lower ptr/int bitcasts in IRTranslator to support the byte type (PR #196125)

[Matt Arsenault via llvm-commits]

https://github.com/arsenm commented:

This is a representational question for how to represent the byte type in gMIR, and this is probably the wrong answer. We've been using scalar essentially the same way as the byte type, so we probably should continue on that route and allow bitcast to scalar. The main question I think is if we need to maintain the distinction between integer and byte type 

https://github.com/llvm/llvm-project/pull/196125